import {
    INCREMENTCOUNT,
    DECREMENTCOUNT
}from '../constant/countConst'
// 定义reducer的初始值
const init={
    count:0
}

export default function countReducer(prevStata=init,action){
    //接受action对象的type和data
    const {
        type,
        data
    }=action;
    switch(type){
        case INCREMENTCOUNT:
            return {
                ...init,count:prevStata.count+data
            };
        case DECREMENTCOUNT:
            return {
                ...init,count:prevStata.count-data
            };  
    }
   return prevStata;
}